implemented where clause into parser

src/lex_lexer.l

@@ -43,13 +43,20 @@ OR		TOK(OR)
 "<"		|
 ">"		|
 "<="	|
-">="	TOK(COMPARISON)
+">="	{
+	yylval->sval = strdup(yytext);
+	return COMPARISON;
+}
+
 
 [-+*/(),.;]	TOK(yytext[0])
 
 [0-9]+	|
 [0-9]+"."[0-9]* |
-"."[0-9]*	TOK(INTNUM)
+"."[0-9]*	{
+	yylval->number = atof(yytext);
+	return INTNUM;
+}
 
 [A-Za-z][A-Za-z0-9_]* {
 	yylval->sval = strdup(yytext);

src/lex_parser.y

@@ -36,7 +36,7 @@ typedef void* yyscan_t;
 %parse-param { yyscan_t scanner }
 
 %union {
-	int value;
+	float number;
 	char* sval;
 
 	Statement* statement;
@@ -49,14 +49,18 @@ typedef void* yyscan_t;
 }
 
 %token SELECT FROM GROUP BY WHERE NOT AND OR
-%token INTNUM COMPARISON STRING
-%token <sval> NAME
+
+%token <sval> NAME STRING COMPARISON
+%token <number> INTNUM
 
 %type <statement> statement
 %type <select_statement> select_statement
-%type <sval> column_name table_name
+%type <sval> table_name
 %type <table> from_clause table_exp
-%type <expr> expr;
+
+%type <expr> expr column_name scalar_exp literal
+%type <expr> comparison_predicate predicate search_condition where_clause
+
 %type <slist> table_ref_commalist
 %type <explist> expr_list group_clause
 %%
@@ -80,6 +84,7 @@ select_statement:
 			SelectStatement* s = new SelectStatement();
 			s->_select_list = $2;
 			s->_from_table = $3;
+			s->_where_clause = $4;
 			s->_group_by = $5;
 			$$ = s;
 		}
@@ -92,8 +97,8 @@ from_clause:
 	;
 
 where_clause:
-		WHERE search_condition
-	|	/* empty */
+		WHERE search_condition { $$ = $2; }
+	|	/* empty */ { $$ = NULL; }
 	;
 
 group_clause:
@@ -126,12 +131,12 @@ predicate:
 	;
 
 comparison_predicate:
-		scalar_exp COMPARISON scalar_exp
+		scalar_exp COMPARISON scalar_exp { $$ = makePredicate($1, $2, $3); }
 	;
 
 
 expr:
-		column_name { $$ = makeColumnRef($1); }
+		column_name
 	|	NAME '(' expr ')' { $$ = makeFunctionRef($1, $3); }
 	;
 
@@ -153,7 +158,7 @@ table_ref_commalist:
 
 
 column_name:
-		NAME
+		NAME { $$ = makeColumnRef($1); }
 	;
 
 table_name:
@@ -162,8 +167,8 @@ table_name:
 	;
 
 literal:
-		STRING
-	|	INTNUM
+		STRING { $$ = makeStringLiteral($1); }
+	|	INTNUM { $$ = makeFloatLiteral($1); }
 	;
 
 scalar_exp:

src/lib/Expr.cpp

@@ -1,6 +1,6 @@
 
 #include "Expr.h"
-
+#include <stdio.h>
 
 Expr* makeColumnRef(char* name) {
 	ALLOC_EXPR(e, eExprColumnRef);
@@ -12,5 +12,26 @@ Expr* makeColumnRef(char* name) {
 Expr* makeFunctionRef(char* func_name, Expr* expr) {
 	ALLOC_EXPR(e, eExprFunctionRef);
 	e->name = func_name;
+	e->expr = expr;
+	return e;
+}
+
+Expr* makePredicate(Expr* expr1, char* op, Expr* expr2) {
+	ALLOC_EXPR(e, eExprPredicate);
+	e->name = op;
+	e->expr = expr1;
+	e->expr2 = expr2;
+	return e;
+}
+
+Expr* makeFloatLiteral(float value) {
+	ALLOC_EXPR(e, eExprLiteralFloat);
+	e->float_literal = value;
+	return e;
+}
+
+Expr* makeStringLiteral(char* string) {
+	ALLOC_EXPR(e, eExprLiteralString);
+	e->name = string;
 	return e;
 }

src/lib/Expr.h

@@ -17,9 +17,12 @@ struct Expr {
 
 	char* name;
 	Expr* expr;
+	Expr* expr2;
+	float float_literal;
 };
 
 // Zero initializes an Expr object and assigns it to a space in the heap
+// http://www.ex-parrot.com/~chris/random/initialise.html
 #define ALLOC_EXPR(var, type) 		\
 	Expr* var;						\
 	do {							\
@@ -31,6 +34,9 @@ struct Expr {
 
 Expr* makeColumnRef(char* name);
 Expr* makeFunctionRef(char* func_name, Expr* expr);
+Expr* makePredicate(Expr* expr1, char* op, Expr* expr2);
+Expr* makeFloatLiteral(float value);
+Expr* makeStringLiteral(char* string);
 
 
 #endif

src/lib/Statement.h

@@ -34,6 +34,7 @@ public:
 	TableRef* _from_table;
 	List<Expr*>* _select_list;
 	List<Expr*>* _group_by;
+	Expr* _where_clause;
 };
 
 

src/sql_tests.cpp

@@ -18,20 +18,28 @@ void SelectTest1() {
 	fflush(stdout);
 
 	const char* sql = "SELECT age, name, address from table WHERE age > 12.5;";
-	Statement* stmt = SQLParser::parseSQL(sql);
-	ASSERT(stmt != NULL);
-	ASSERT(stmt->_type == eSelect);
+	Statement* sqlStatement = SQLParser::parseSQL(sql);
+	ASSERT(sqlStatement != NULL);
+	ASSERT(sqlStatement->_type == eSelect);
 
-	SelectStatement* select = (SelectStatement*) stmt;
+	SelectStatement* stmt = (SelectStatement*) sqlStatement;
 
-	ASSERT(select->_select_list->size() == 3);
-	ASSERT_STR(select->_select_list->at(0)->name, "age");
-	ASSERT_STR(select->_select_list->at(1)->name, "name");
-	ASSERT_STR(select->_select_list->at(2)->name, "address");
+	ASSERT(stmt->_select_list->size() == 3);
+	ASSERT_STR(stmt->_select_list->at(0)->name, "age");
+	ASSERT_STR(stmt->_select_list->at(1)->name, "name");
+	ASSERT_STR(stmt->_select_list->at(2)->name, "address");
 
-	ASSERT(select->_from_table != NULL);
-	ASSERT(select->_from_table->_type == eTableName);
-	ASSERT_STR(select->_from_table->_table_names->at(0), "table");
+	ASSERT(stmt->_from_table != NULL);
+	ASSERT(stmt->_from_table->_type == eTableName);
+	ASSERT_STR(stmt->_from_table->_table_names->at(0), "table");
+
+	// WHERE
+	ASSERT(stmt->_where_clause != NULL);
+	ASSERT(stmt->_where_clause->expr->type == eExprColumnRef);
+	ASSERT_STR(stmt->_where_clause->expr->name, "age");
+	ASSERT_STR(stmt->_where_clause->name, ">");
+	ASSERT(stmt->_where_clause->expr2->type == eExprLiteralFloat);
+	ASSERT(stmt->_where_clause->expr2->float_literal == 12.5);
 
 	printf("passed!\n");
 }